Urban coastal flood inundation modelling: a case study of Thane City, India

Abstract

In this paper, the flood simulation of a coastal urban city is presented using the integrated approach of hydrological model, remote sensing and Geographical Information System (GIS). For hydrological simulation, a mass balance–based overland flow model and diffusion wave–based model for channel flow is considered. Effect of tidal variation is considered as the boundary condition. GIS is used for data management whereas remote sensing is used for land use classification. The model is applied to Thane city catchment, Maharashtra, India to simulate the channel flooding for two rainfall events. The simulated water levels are compared with some observed values to serve as validation for the model and are found to be in reasonable agreement. Parameter-based sensitivity analysis for the catchment revealed that peak discharge variation is more sensitive to overland roughness than channel roughness. However, stage (water level) variation is more sensitive to channel roughness. Time-step sensitivity indicated that model results are stable for a limited range of time step.

Keywords:

• coastal urban flooding
• hydrological model
• Geographic Information System
• remote sensing

Acknowledgements

The authors acknowledge the Department of Science and Technology, Government of India, New Delhi, for sponsoring the 09DST033 project. The authors also thank the staff of Thane Municipal Corporation, Maharashtra—K. Lalla, M. Hirlekar, D. Shinde and M. Pradhan—for providing data related to the drainage and rainfall for the study.